Concentration of sylvinite ores



Patented Aug. 8,1944

CONCENTRATION OF SYLVINITE ORES Allen T. Cole, Lakeland, Fla., assignor, by mesne assignments, to Minerals Separation North American Corporation, New York, N. Y., a corporation of Maryland No Drawing. Application December 23, 1942, Serial No. 469,915

19 Claims.

This invention relates to the concentrating, or separation of the values from soluble ores. More particularly, it relates to the separation of sylvite (potassium chloride-RC1) from a saturated solution of the soluble constituents of sylvinite ores such, for example, as those found in the Carlsbad district of New Mexico.

The invention resides in improved methods of effecting the separation of the desired sylvite from such ores by froth flotation, skin flotation, agglomeration ,tabling and other methods involving wet stratiflcation with the use of appropriate agents which eifect the separation of the sylvite from the other ore constituents.

It is already known that sylvite can be recovered from a saturated solution of the soluble constituents of sylvinite ore in accordance with well-established concentration operations by using as a collector an aliphatic amine containing a straight chain hydrocarbon group of at least 7 carbon atoms, or the salts of such aminesv resulting from. their combination with watersoluble acids.

The general objects of the present invention are to produce concentrates of the desired sylvite which are of high commercial grade, with high percentages of recovery, with economy in the use of reagents and with reliable and easily controlled operation of the plant. These objects are attained by the processes embodying the Present invention which are hereinafter described.

The methods of the present invention are the result of the discovery that greatly improved results, as to grade and recovery of the desired sylvite and as to control of operations, can be obtained by the use, in conjunction with the aforesaid straight chain alkyl amines used as collectors, of lignin derivatives which are watersoluble or capable of being colloidally dispersed in water, such derivatives being used as auxiliary agents.

The straight chain alkyl amines useful as collectors for sylvite, the action of which is improved by the concurrent use of lignin derivatives as auxiliary collecting agents, include the following aliphatic primary amines: n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and n-octadecenylamine. The lower members of this series may be added to the ore pulp in the form of the free base or as the salts formed by their combination with acids which are themselves relatively devoid of surface active properties, such, for example, as hydrochloric acid, nitric acid, acetic acid, etc. The higher members of the series, being much less soluble, are generally used in the form of their more soluble salts.

These amine collectors may be used individually or as mixtures. The mixtures need not necessarily consist only of aliphatic primary amines or their salts but may also contain varying proportions of aliphatic secondary and tertiary amines or their salts, such as are commonly found in commercial products. For example, the product of Armour and Company sold under the designation Am. Ac. 1180-0 is very suitable and is understood to consist of approximately 73% mono-octadecylamine acetate, about 24% mono-hexadecylamine acetate, together with small quantities of secondary and tertiary amine acetates. Another suitable commercial product is that sold by E. I. du Pont de Nemours & Company, Inc., as D. P. 243 which is a 50% aqueous paste of technical laurylamine hydrochloride understood to contain approximately 18% octylamine hydrochloride, 10% decylamine hydrochloride, laurylamine hydrochloride, 17% myristylamine hydrochloride, and traces of secondary and tertiary amines.

Lignin, as the term is used herein and in the claims, refers to the non-cellulosic component of such vegetable cells as those of the various woods, bark, corn stalks, cereal hulls, straw, flax, peanut hulls, bagasse, etc., and is inclusive of substances sometimes referred to as lignone and lignose.

The lignin may be, and most commonly is, isolated from wood or other plant material by subjecting it to a hydrolytic reaction aided by the use of mineral acids, organic acids, alkalies, pulping chemicals, fungi or hydrolytic enzymes, some of which may be present in the woody material treated. The usual methods of extracting lignin from the vegetable cells are those used in the paper pulp industry, in which lignin is removed in the course of obtaining the pulp by the sulflte, sulfate and soda pulp processes, the

waste or black liquor from these processes containing the lignin. The chemical formula of lignin is believed to be still in the realm of speculation and lignin, as the term is here used, may be a complex material.

Lignin compounds or derivatives of various kinds may be obtained from the waste or black liquor, the compound obtained depending upon the particular pulping process employed and the treatment used to extract the lignin compound from the waste liquor.

A product commercially available and known as alkali lignin may be obtained from The Mead Corporation, of Chillicothe, Ohio, under the tradename Meadol. It is stated by the manufacturer to be prepared from black liquor produced in the soda pulp process by precipitating with carbon dioxide. This product might be considered to be sodium lignate. Other alkali metal lignates may be produced by analogous processes.

The salts of lignin sulfonates may be produced by fractional precipitation from the waste liquor of the sulfite and sulfate pulp processes. Sodium lignin sulfonate (sodium lignosulfonate) and calcium lignin sulfonate (calcium lignosulfonate) may be obtained from the Marathon Chemical Company, of Rothschild, Wisconsin.

Lignin sulfonic acid (lignosulfonic acid) may be prepared by suspending the alkaline earth metal lignosulfonate in water, adding just enough sulfuric acid to precipitate the alkaline earth metal as the sulfate and removing the precipitate.

Lignin sulfonates may be used in the process of the present invention in the form of the free acid or as the alkali metal or alkaline earth salts.

The foregoing is illustrative of various lignin derivatives but it is within the scope of the invention to use as an auxiliary collecting agent with amine collectors any lignin derivative which is water-soluble or capable of being colloidally dispersed in water, regardless of the method by which it may be prepared. Specifically it is intended to include lignosulfite, sulfonates of lignin (both the free acid and salts) and sulfo-containing derivatives of lignin.

The following specific examples of embodiments of the invention show, by comparison with the comparative tests in which no lignin derivative was used, the advantages to be obtained from the use of these compounds as auxiliary collecting agents.

In practicing the methods of the present invention desliming of the sylvinite ore is desirable; and it is also sometimes desirable to add a frothing agent, such as pine oil, in addition to the collector and the lignin, when the desired mineral is to be concentrated by froth flotation, or a petroleum oil such as fuel oil when concentration is to be effected by tabling.

Comparative test A.-Sylvinite ore from Carlsbad, New Mexico, was crushed so that it would pass through a -mesh screen, and was then deslimed and ground so that it would pass through a 35-mesh screen, after which it was made into a pulp of about 20% solids with a saturated solution of ore constituents. Reagent, as hereinafter specified, was added to this pulp, the pulp was agitated about 10 seconds to distribute the reagent and flotation was then effected. The first or rougher froth concentrate was returned to the flotation machine, diluted and refloated. This was repeated on the second froth concentrate. The reject of the first flotation operation was final tailings. Rejects of the second and third flotation operations were middlings to be returned to the flotation circuit and further values recov-' ered therefrom. The reagent used was Am. Ac. 1180-0" in amount of 1.00 lb. per ton of ore treated. The results were as follows:

Per cent Per cent KC] re- Pmduct weight KCl covery Feed 100. 0 29. 2 100.0 Concentrate 6. 9 03. 7 18.9 9. 6 89. 0 29. 5 l6. 0 61. 7 33. 8 63. 3 6. 3 13.8 5. 2 22. 2 4. O

Per cent Per cent K01 re- Pmduct weight KCl covery It will be noted that the use of sodium lignosulfonate in conjunction with the other reagent, as is shown by comparison of this example with Comparative test A, improved the recovery by 58.3% (77.2% KCl recovery when sodium lignosulfonate was used, as against 18.9% KCl recovery without it) and increased the grade slightly by 0.4% (94.1% as against 93.7%).

Comparative test B.-This test will serve as a basis of comparison for Examples 2 and 3 which follow. The ore, preparation of the feed and procedure were the same as in Comparative test A, 1.00 lb. per ton of ore of Am. Ac. 1180-0" was used as in the preceding test but with the addition of 0.2 lb. per ton of ore of pine oil. The results were as follows:

Per cent Per cent KCl re- Pmdmt weight KCl covery Feed 100.0 31. 2 100.0 Concentrate 15. 6 90. 9 45. 4 M ddl ng 2- 6.0 86. 1 16.6 Middhng 1.-. 8.9 62.6 17.8 Telling 64. 4 7. 2 l4. 8 Slime .5. l 33. 2 5. 4

Example 2.-The ore, procedure and reagents were the same'as in Comparative test B except that there was added to the pulp 0.8 lb. per ton of ore of lignosulfonic acid in the form of a 3% aqueous solution. The results were as follows:

By comparison of Example 2 with Comparative test B, it will be seen that the addition of the lignosulfonic acid increased recovery by 30.9% and increased the grade by 3.0

Example 3.The ore, procedure and reagents Per cent Per cent KCl re- Pmduct weight KCl covery Feed 100. 27. 9 100. 0 Concentrate. 24. 1 89.0 77.0 Mlddling 2. 3. 4 69. 0 7. 2 Middling 1.. 7. 6 l9. 6 5. 3 Telling 60. 4 2. 9 6. 4 Slime 4. 6 25. 3 4. 1

stituents went off at the end of the table. The results were as follows:

Per cent Per cent KC] rc 5 Product weig KC! covery Feed 100. 0 28. 6 mo. 0 Concentrate. 14. 3 07. 2 48. 6 Middllng 2 7. 8 72. 4 l9. 6 Mi d dli.ug 1.. 9. 3 21. 4 7. 0 Tallmg 67. 4 l0. 4 24. 5 10 Slime 1. 2 12.0 0. a

Example 5.The ore, procedure and reagent were the same as in Test D except that 0.4 lb. per ton of ore of sodium lignosulfonate was IOWS Per cent Per cent KCl re- Pwduct weight K covery Feed 100. 0 29. 0 100. 0 Concentrate l6. 5 88. 2 50. 2 5. 4 06. 2 12. 3 l0. 5 36. 0 13. 1 60. 8 8. 9 l8. 7 6. 8 24. 5 5. 7

Example 4.-The ore, procedure and reagents were identical with those used in Comparative test C except that there was added to the pulp 0.8 lb. per ton of ore of alkali lignin (sodium lignate) in the form of a 3% solution in diethylene glycol. The results were as follows:

Per cent Per cent KCI re- Product weight KCl covery By comparison of Example 4 with Comparative test C, it will be seen that the addition of the alkali lignin increased the recovery by 13.3% while the grade was substantially the same.

Comparative test D.This test in comparison with Example 5 shows the beneficial effect of using a lignin derivative as an auxiliary collecting agent in the recovery of sylvite by table concentration methods. The ore was from the same source as that used in the preceding examples and was first reduced to particle sizes ranging from about minus 6 to about plus 35 mesh and then partially deslimed. It was then made up to a pulp in which the ratio of brine to ore was 1:1.88 by weight and conditioned with the reagent for about one minute. The sole reagent was Am. Ac. 1180-C 0.5 lb. per ton of ore. The conditioned pulp was fed to a shaking table with a saturated aqueous solution of soluble ore constituents. The sylvite concentrate was recovered at the side of the table and the rejected conadded, in aqueous solution, as an auxiliary collecting agent. The results were as follows:

Per cent Per cent KC] re- Pmduc weight K01 covery Feed 100.0 26.4 100.0 Concentrate 20. 7 96. 4 75. 5 Mlddlmg 2-.. 1.2 87.3 4.0 Middling 1 1. 4 34. 2 1.8

By comparison of Test D and Example 5, it will be seen that the addition of the sodium lignosulfonate increased recovery by 26.9% with an insignificant drop in grade of only 0.8%.

It is to be understood that the foregoing examples are merely illustrative of the present invention and that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

What is claimed is:

1. The improvement in the method of separating sylvite from a pulp containing it which comprises subjecting said pulp to a concentrating process employing a collector selected from the group consisting of aliphatic amines containing a straight chain hydrocarbon group of at least 7 carbon atoms and their soluble salts formed by their combination with acids which are relatively devoid of surface active properties, which resides in distributing in said pulp a useful amount of an auxiliary collecting agent selected from the class consisting of lignin derivatives which are water-soluble or capable of being colloidally dispersed in water, and thereafter subjecting the pulp to a separation treatment to remove the desired sylvite.

2. A method as set forth in claim 1, wherein the pulp is formed from sylvinite ore and a substantially saturated aqueous solution of the soluble ore constituents.

3. A method as set forth in claim 1, wherein the sylvinite ore is substantially deslimed before the collector and the auxiliary collecting agent are added.

4. A method as set forth in claim 1, wherein the separation treatment is a froth-flotation treatment in a froth-flotation machine.

5. A method as set forth in claim 1, wherein the separation treatment is an agglomeration tabling treatment.

6. A method as set forth in claim 1, wherein a frothing agent is used in conjunction with the collector and auxiliary collecting agent and the separation of the sylvite is eifected by froth flotation.

7. A method as set forth in claim 1, wherein a petroleum oil is used in conjunction with the collector and auxiliary collecting agent, the

sylvite agglomerated and the agglomerates seprated.

8. A method as set forth in claim 1, wherein the auxiliary collectingagent is an alkali metal lignin compound.

9. A method as set forth in claim 1, wherein the auxiliary collecting agent is a sulfa-containing derivative of lignln.

10. A method as set forth in claim 1, wherein the auxiliary collecting agent is an alkali metal lig'nin sulfonate.

11. A method as set forth in claim 1, wherein the auxiliary collecting agent is lignosulfonic acid.

12. A method as set forth in claim 1, wherein the auxiliary collecting agent is sodium lignosulfonate.

13. A method as set forth in claim 1, wherein the auxiliary collecting agent is, lignosulflte.

14. A method as set forth in claim 1, wherein the auxiliary collecting agent is a salt of a lignln sulfonic acid.

15. A method as set forth in claim 1, wherein octadecylamine acetate is used as the collector.

16. A method as set forth in claim 1, wherein n-heptylamine acetate is used as the collector.

17. A method as set forth in claim 1, wherein laurylamine hydrochloride is used as the collector.

18. A method as set forth in claim 1, wherein octadecylamine acetate is used as the collector in conjunction with a frothing agent and separation is eflected by froth-flotation to remove the sylvite.

19. A method as set forth in claim 1, wherein octadecylamine acetate is used as the collector in conjunction with a petroleum oil and separation is effected by agglomeration tabling treatment to remove the sylvite;

ALLEN T. COLE. 

